In a variety of technologies involving the use of liquid chemicals the elimination of water and associated impurities is necessary before such chemicals can be reused. For example, a number of technologies use large volumes of solvents and solvent mixtures for drying. Thus, in the manufacturing process of electronic and semiconductor devices, parts, such as integrated circuit wafers and printed circuit boards must be water-rinsed between subsequent steps of fabrication. Since these parts are extremely sensitive to impurities, water-rinsing must be followed by quick and efficient drying to avoid the formation of drying stains on their surfaces, which would adversely effect the performance of the target devices.
According to a widely used procedure, the water and associated dissolved and particulate impurities are removed by vapor drying with a liquid solvent or solvent mixture. For this purpose, large quantities of organic solvents and solvent systems are used.
After drying, the used organic solvents contain varying amounts of water and (dissolved and undissolved) impurities, and are normally disposed of as waste.
Whereas traditionally isopropyl alcohol (IPA) and Chloro-Fluoro-Carbons (CCFC's) were the choice of solvents for vapor drying, due to the potential fire hazard associated with the former one, and the ban on CFCs, the focus is more and more on the development of new solvents and solvent systems. Most of these are rather expensive, and potentially health hazardous, therefore, their discharge poses serious environmental problems. It is, therefore, highly desirable to have a system suitable for the safe, efficient regeneration of such solvents, including those containing two or more phases.
The object of the present invention is to provide a method for the regeneration and purification of water-containing liquids, such as solvents and solvent systems, in particular of used vapor drying solvents.
Another specific object of this invention is to provide a novel apparatus for the regeneration and purification of such liquids, in particular of used vapor drying solvents.